A multi-cavity coaxial transmission line structure for antenna feeding network

Abstract

The present invention provides a multi-cavity coaxial transmission line structure for an antenna feeding network, which relates to the field of communication antennas, and includes a multi-cavity metal profile and a signal transmission line arranged in the multi-cavity metal profile; the multi-cavity metal profile is an integrally formed part, and a plurality of cylindrical cavities parallel to each other are arranged inside the multi-cavity metal profile; the signal transmission line has one or more lines, which are respectively arranged in one or more cylindrical cavities of the multi-cavity metal profile; each signal transmission line includes one or more sections of metal tubes, which are supported in the cylindrical cavity of the multi-cavity metal profile through a supporting connector and are coaxially arranged with the cylindrical cavity; the multi-cavity metal profile is grounded, and the metal tube is electrically connected to an external feeding power source, and is used to transmit a feeding signal in a TEM mode in the cylindrical cavity. The present invention improves the flexibility and applicability of the feeding signal transmission structure, and reduces the production cost and transmission loss of the antenna feeding network.

Description

Technical Field

[0001] The present invention relates to the field of communication antennas, and in particular to a multi-cavity coaxial transmission line structure for an antenna feeding network. Background Art

[0002] The feed network is an important component of the base station antenna. It is connected between the antenna port and the radiating element array, forming a path for RF signal transmission and realizing impedance matching, amplitude and phase distribution and other functions. The feed network is closely related to the performance of the base station antenna. Its main function is to transmit the high-frequency current from the transmitter to the radiating element, or to transmit the high-frequency current from the radiating element to the transmitter.

[0003] In the existing feeding network, the main transmission modes of the feeding signal are stripline transmission and microstrip line transmission. Among them, the feeding network based on stripline transmission usually includes an aluminum profile cavity with a rectangular cross-section and a PCB board arranged in the aluminum profile cavity, and the PCB board is printed with circuit structures such as power dividers and phase shifters formed by the stripline network; the stripline transmission is achieved by grounding the aluminum profile cavity so that its upper and lower side walls are equivalent to two parallel grounding plates. The feeding network based on microstrip line transmission is mainly composed of a PCB board, one side of the PCB board is printed with circuit structures such as power dividers and phase shifters formed by the microstrip line network, and the other side of the PCB board is printed with a metal floor.

[0004] However, the feeding networks using these two transmission modes have some defects to a greater or lesser extent.

[0005] First, both feed networks have the problem of too much customization and insufficient flexibility. Specifically, both stripline and microstrip lines need to be printed on PCB boards, which makes the distribution and design indicators of the feed network relatively fixed and difficult to reuse; when the application scenario and design requirements of the feed network change, it is necessary to redesign and print different PCB boards.

[0006] Second, both feed networks have the problem of high production costs. On the one hand, the PCB board cost for printing strip lines and microstrip lines is high, resulting in high overall production costs for related structures. On the other hand, when wiring the stripline-based feed network, the aluminum profile cavity needs to be welded and electroplated, which increases labor costs and process costs, and the high degree of manual participation is not conducive to automated production.

[0007] Third, both feeding networks have different degrees of transmission loss. On the one hand, in the feeding network based on stripline transmission, the main mode of stripline transmission is TEM (transverse electromagnetic wave) mode, and its electric field and magnetic field directions are perpendicular to the propagation direction of the wave. Since all striplines are encapsulated in the same closed aluminum profile cavity through PCB boards, the electromagnetic waves generated by each stripline during signal transmission repeatedly oscillate and influence each other between the upper and lower ground planes, resulting in inevitable interference between the branches, which will introduce transmission loss and reduce transmission efficiency. On the other hand, in the feeding network based on microstrip line transmission, the main mode of microstrip line transmission is quasi-TEM mode, and its electric field and magnetic field are mainly transverse, but there is a small longitudinal component, which causes the microstrip line to form surface waves at the edge of the microstrip line during signal transmission, resulting in the loss of some energy radiation to the outside. In addition, since the main mode of the coaxial cable used to introduce the external feeding signal is the TEM mode, there is a conversion of different transmission modes at the connection between the coaxial cable and the microstrip line, which will cause discontinuity in transmission and thus produce discontinuity loss. The more times the different transmission modes are converted, the greater the loss generated.

[0008] It can be seen that the feed signal transmission structure in the prior art has the defects of poor flexibility, high cost and large loss, and needs to be improved and perfected. Summary of the invention

[0009] The purpose of the present invention is to provide a multi-cavity coaxial transmission line structure for an antenna feeding network to address the problems existing in the prior art, thereby improving the flexibility and applicability of the feeding signal transmission structure and reducing the production cost and transmission loss of the antenna feeding network.

[0010] To achieve the above object, the present invention adopts the following technical solutions:

[0011] A multi-cavity coaxial transmission line structure for an antenna feeding network, comprising a multi-cavity metal profile and a signal transmission line arranged in the multi-cavity metal profile;

[0012] The multi-cavity metal profile is an integrally formed part, and a plurality of cylindrical cavities parallel to each other are arranged inside the multi-cavity metal profile. The plurality of cylindrical cavities penetrate the multi-cavity metal profile along the Y-axis direction and are arranged side by side in sequence along the X-axis direction;

[0013] There are one or more signal transmission lines, which are respectively arranged in one or more cylindrical cavities of the multi-cavity metal profile; each signal transmission line comprises one or more sections of metal tubes, which are supported in the cylindrical cavity of the multi-cavity metal profile by a supporting connector and are coaxially arranged with the cylindrical cavity; the supporting connector is made of an insulating medium, so that the metal tube and the multi-cavity metal profile do not contact each other and are not conductive to each other;

[0014] The multi-cavity metal profile is grounded, and the metal tube is electrically connected to an external power supply for transmitting a feeding signal in a TEM mode in a cylindrical cavity.

[0015] Furthermore, by designing the inner diameter of the cylindrical cavity or the outer diameter of the metal tube to have different size specifications, signal transmission lines with different characteristic impedances can be realized.

[0016] Furthermore, in the same signal transmission line, two sections of metal tubes with different outer diameters are connected by a connecting column to achieve impedance transformation of the signal transmission line;

[0017] The connecting column is made of the same material as the metal tube, the outer diameter of one end of the connecting column matches the inner diameter of one section of the metal tube, the outer diameter of the middle part of the connecting column matches the outer diameter of one section of the metal tube, and the outer diameter of the other end of the connecting column matches the inner diameter of the other section of the metal tube; the two ends of the connecting column are respectively inserted and connected to the ends of the two sections of the metal tube, so that the two sections of the metal tube are connected to each other and conductive.

[0018] Furthermore, the multi-cavity metal profile is an aluminum profile, which is made by an integrated pultrusion process.

[0019] Furthermore, the metal tube is a metal copper tube, an electroplated aluminum tube or an electroplated die-cast aluminum alloy tube.

[0020] Furthermore, the inner diameter of the cylindrical cavity is 6-9 mm, and the outer diameter of the metal tube is 1.1-5 mm.

[0021] Furthermore, the inner diameter of the cylindrical cavity is 8 mm, and the outer diameter of the metal tube is 1.5-4.5 mm.

[0022] Further, the supporting connecting member is an integrally formed member, comprising two arc-shaped supporting arms located on both sides and a fixing pin located in the middle; one ends of the two arc-shaped supporting arms are connected to each other, and the middle parts are respectively bent outwards, so that a circular arc buckle is formed between the two arc-shaped supporting arms, and the other ends of the two arc-shaped supporting arms are arranged opposite to each other to form an opening of the circular arc buckle; one end of the fixing pin is connected to the connection of one ends of the two arc-shaped supporting arms, and the other end of the fixing pin extends radially to the opening of the circular arc buckle;

[0023] The metal tube is provided with a fixing hole which penetrates radially, and the fixing pin of the supporting connection piece passes radially through the fixing hole on the metal tube. The inner diameter of the arc-shaped buckle between the two arc-shaped supporting arms matches the outer diameter of the metal tube, so that the metal tube is fixed in the arc-shaped buckle; the outer contour diameter of the two arc-shaped supporting arms matches the inner diameter of the cylindrical cavity, so as to support the metal tube in the cylindrical cavity of the multi-cavity metal profile, and make the axis of the metal tube coincide with the axis of the cylindrical cavity.

[0024] Furthermore, the supporting connector is in the shape of a circular ring, and its inner diameter matches the outer diameter of the metal tube, and the outer diameter matches the inner diameter of the cylindrical cavity; the supporting connector is sleeved on the outside of the metal tube to support the metal tube in the cylindrical cavity of the multi-cavity metal profile, and to make the axis of the metal tube coincide with the axis of the cylindrical cavity.

[0025] Furthermore, the supporting connector is made of PTFE material or PPS material.

[0026] The present invention forms a multi-cavity coaxial transmission line structure through a multi-cavity metal profile and a metal tube arranged therein, does not require the use of a PCB board, and the multi-cavity metal profile does not require welding and electroplating during wiring, which reduces production costs and improves the intermodulation stability of the circuit; at the same time, it is more suitable for automated production and improves production efficiency.

[0027] The present invention uses a cylindrical cavity of a multi-cavity metal profile as an outer conductor and a metal tube as an inner conductor, thereby realizing a transmission mode with the TEM mode as the main mode, reducing the radiation loss of the feed signal during the transmission process, and being almost free from interference from external signals. In addition, each cylindrical cavity is completely isolated from each other, and the coupling between each cylindrical cavity is zero, which can effectively avoid the electromagnetic waves generated by each signal transmission line from influencing each other, reducing the transmission loss of the feed signal, and greatly improving the transmission efficiency.

[0028] On this basis, the present invention can also flexibly adjust the characteristic impedance of the signal transmission line structure by changing the inner diameter of the cylindrical cavity or the outer diameter of the metal tube to adapt to different engineering design requirements. It has sufficient flexibility and applicability and has broad application prospects.

[0029] In summary, the multi-cavity coaxial transmission line structure for an antenna feeding network provided by the present invention improves the flexibility and applicability of the feeding signal transmission structure and reduces the production cost and transmission loss of the antenna feeding network. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall structure of a multi-cavity coaxial transmission line structure for an antenna feeding network provided by an embodiment of the present invention.

[0031] Figure 2 It is a schematic diagram of the internal structure of a multi-cavity coaxial transmission line structure for an antenna feeding network provided by an embodiment of the present invention.

[0032] Figure 3 Schematic diagram of the structure of the metal tube in the embodiment of the present invention.

[0033] Figure 4 It is a schematic structural diagram of a supporting connecting member in an embodiment of the present invention.

[0034] Figure 5 Schematic diagram of the structure of the connecting column in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a multi-cavity coaxial transmission line structure for an antenna feeding network, comprising a multi-cavity metal profile 1 and a signal transmission line arranged in the multi-cavity metal profile 1.

[0037] The multi-cavity metal profile 1 is an integrally formed part, and a plurality of cylindrical cavities 10 parallel to each other are arranged inside the multi-cavity metal profile 1. The plurality of cylindrical cavities 10 penetrate the multi-cavity metal profile 1 along the Y-axis direction and are arranged side by side in sequence along the X-axis direction.

[0038] There are one or more signal transmission lines, which are respectively arranged in one or more cylindrical cavities 10 of the multi-cavity metal profile 1; each signal transmission line comprises one or more sections of metal tubes 2. The metal tubes 2 are supported in the cylindrical cavity 10 of the multi-cavity metal profile 1 by supporting connectors 3, and are coaxially arranged with the cylindrical cavity 10; the supporting connectors 3 are made of insulating medium, so that the metal tubes 2 and the multi-cavity metal profile 1 do not contact each other and are not conductive to each other;

[0039] The multi-cavity metal profile 1 is grounded, and the metal tube 2 is electrically connected to an external power supply for transmitting a feeding signal in a TEM mode in the cylindrical cavity 10 .

[0040] The multi-cavity metal profile 1 can be made of aluminum profile or copper profile, and the metal tube can be made of metal copper tube, electroplated aluminum tube or electroplated die-cast aluminum alloy tube. Preferably, the multi-cavity metal profile 1 in the embodiment of the present invention is an aluminum profile, which is made by an integrated pultrusion process; the metal tube 2 in the embodiment of the present invention is a metal copper tube.

[0041] Combination Figure 3 and Figure 4As shown, the metal tube 2 is provided with a fixing hole 20 which penetrates radially. The supporting connector 3 is an integrally formed part, and can be made of insulating materials with high temperature resistance and low dielectric constant such as PTFE and PPS, so as to minimize the transmission loss of the feeding signal. Specifically, the supporting connector 3 includes two arc-shaped support arms 31 located on both sides and a fixing pin 32 located in the middle; one ends of the two arc-shaped support arms 31 are connected to each other, and the middle parts are respectively bent outward, so that an arc-shaped buckle is formed between the two arc-shaped support arms 31, and the other ends of the two arc-shaped support arms 31 are relatively arranged to form an opening of the arc-shaped buckle; one end of the fixing pin 32 is connected to the connection of one end of the two arc-shaped support arms 31, and the other end of the fixing pin 32 extends radially to the opening of the arc-shaped buckle.

[0042] During installation, the fixing pin 32 of the supporting connector 3 is radially passed through the fixing hole 20 on the metal tube 2. Since the inner diameter of the arc-shaped buckle between the two arc-shaped supporting arms 31 matches the outer diameter of the metal tube 2, the metal tube 2 is fixed in the arc-shaped buckle; the outer contour diameter of the two arc-shaped supporting arms 31 matches the inner diameter of the cylindrical cavity 10, so as to support the metal tube 2 in the cylindrical cavity 10 of the multi-cavity metal profile 1, and make the axis of the metal tube 2 coincide with the axis of the cylindrical cavity 10.

[0043] The advantage of the support connector 3 in this embodiment is that it is easy to install. The support connector 3 can be fixed on the metal tube 2 by a simple press-and-snap installation method. It should be noted that in other embodiments, the support connector 3 can also adopt other feasible simplified structures. For example, a circular ring-shaped support connector 3 (not shown) can also be used, and the metal tube 2 is passed through several support connectors 3 in the axial direction, so that the circular ring-shaped support connector 3 is sleeved on the outside of the metal tube 2, and the inner diameter of the support connector 3 matches the outer diameter of the metal tube 2, and the outer diameter of the support connector 3 matches the inner diameter of the cylindrical cavity 10, so as to support the metal tube 2 in the cylindrical cavity 10.

[0044] Based on the above features, the embodiment of the present invention uses a multi-cavity metal profile 1 and a metal tube 2 to realize a transmission structure equivalent to a coaxial line. A coaxial line is a transmission line composed of two coaxial cylindrical conductors, with air or a high-frequency medium filled between the inner and outer conductors. The main mode of coaxial line transmission is the TEM mode, and its electric field and magnetic field are both in a plane perpendicular to the propagation direction.

[0045] Specifically, each cylindrical cavity 10 inside the multi-cavity metal profile 1 in this embodiment can be equivalent to the outer conductor of a coaxial line, and the metal tube 2 disposed in the cylindrical cavity 10 is equivalent to the inner conductor of the coaxial line. The metal tube 2 transmits the feeding signal in the cylindrical cavity 10 in the TEM mode. The electric field of the TEM mode points from the outer wall of the inner conductor to the inner wall of the outer conductor, and the magnetic field is distributed around the inner conductor. This mode has no radiation loss during the transmission process and is almost not interfered by external signals.

[0046] On this basis, the multiple cylindrical cavities 10 and the metal tube 2 in the multi-cavity metal profile 1 are equivalent to providing multiple parallel and independent signal transmission lines to realize the transmission of the feed signal in the antenna feed network. Among them, since each cylindrical cavity 10 is completely isolated, the coupling between each cylindrical cavity 10 is zero, which can effectively avoid the electromagnetic waves generated by each signal transmission line from affecting each other, reduce the transmission loss of the feed signal, and help to greatly improve the transmission efficiency.

[0047] At the same time, since the multi-cavity metal profile 1 in this embodiment is grounded, all cylindrical cavities 10 have a common ground. For current distribution, having a common ground can not only achieve consistency in current distribution density, but also reduce the current density at a local position, thereby ensuring consistency in overall circuit performance and improving intermodulation indicators.

[0048] In the antenna feeding network, one of the important functions of the transmission line is to achieve impedance transformation and impedance matching. In the embodiment of the present invention, by designing the inner diameter of the cylindrical cavity 10 or the outer diameter of the metal tube 2 to different size specifications, a signal transmission line with different characteristic impedances can be achieved. Taking the impedance of 100 ohms commonly used in the communication industry as an example, if the embodiment of the present invention is to achieve an impedance of 100 ohms, it can be designed according to the following dimensions: when the inner diameter of the cylindrical cavity 10 is 6mm, the outer diameter of the metal tube 2 is 1.12mm; when the inner diameter of the cylindrical cavity 10 is 7mm, the outer diameter of the metal tube 2 is 1.32mm; when the inner diameter of the cylindrical cavity 10 is 8mm, the outer diameter of the metal tube 2 is 1.5mm; when the inner diameter of the cylindrical cavity 10 is 9mm, the outer diameter of the metal tube 2 is 1.7mm.

[0049] Considering that the impedance commonly used in the communication industry is 35-100 ohms, the inner diameter of the cylindrical cavity 10 in the present invention is in the range of 6-9 mm, and the outer diameter of the metal tube 2 is in the range of 1.1-5 mm. The above size range can fully meet the design requirements of the characteristic impedance of 35-100 ohms.

[0050] Furthermore, in the process of producing the multi-cavity metal profile 1 through the integrated pultrusion process, if the inner diameter of the cylindrical cavity 10 is too small, it is difficult to stably pultrude, and if the inner diameter of the cylindrical cavity 10 is too large, the overall size and weight of the multi-cavity metal profile 1 will increase rapidly. After repeated experiments and research, it was found that the preferred inner diameter size of the cylindrical cavity 10 is 8mm. On the one hand, the inner diameter size of 8mm can fully meet the impedance design requirements of different antenna feeding networks, and on the other hand, it can also ensure the production consistency requirements of aluminum profiles in the integrated pultrusion process on the basis of minimization as much as possible, which helps to improve the stability and yield rate when producing multi-cavity metal profiles 1.

[0051] Under the premise that the inner diameter of the cylindrical cavity 10 is fixed at 8mm, if the 35~100 ohm characteristic impedance commonly used in the communications industry is to be achieved, the outer diameter of the metal tube 2 should be set to 1.5~4.5mm. This size design can take into account the low cost and stability requirements in the production process, as well as the flexibility and versatility requirements in the engineering application process. Specifically, when the outer diameter of the metal tube 2 is 4.46mm, the characteristic impedance of the signal transmission line is 35 ohms; when the outer diameter of the metal tube 2 is 3.47mm, the characteristic impedance of the signal transmission line is 50 ohms; when the outer diameter of the metal tube 2 is 2.3mm, the characteristic impedance of the signal transmission line is 75 ohms; when the outer diameter of the metal tube 2 is 1.51mm, the characteristic impedance of the signal transmission line is 100 ohms. Based on the above characteristics, a multi-cavity metal profile 1 with a cylindrical cavity 10 of 8mm with uniform size can be produced in engineering practice, and different impedance transformation and impedance matching design requirements in the antenna feeding network can be realized with metal tubes 2 of different outer diameter specifications.

[0052] Furthermore, combined with Figure 5 As shown, in the same signal transmission line, two sections of metal tubes 2 with different outer diameters can be connected via a connecting column 4 to achieve impedance transformation of the signal transmission line.

[0053] Specifically, the connecting column 4 is made of the same material as the metal tube 2, the outer diameter of one end of the connecting column 4 matches the inner diameter of one section of the metal tube 2, the outer diameter of the middle part of the connecting column 4 matches the outer diameter of one section of the metal tube 2, and the outer diameter of the other end of the connecting column 4 matches the inner diameter of the other section of the metal tube 2; the two ends of the connecting column 4 are respectively inserted and connected to the ends of the two sections of the metal tube 2, so that the two sections of the metal tube 2 are connected to each other and conductive.

[0054] The present invention forms a multi-cavity coaxial transmission line structure through a multi-cavity metal profile and a metal tube arranged therein, does not require the use of a PCB board, and the multi-cavity metal profile does not require welding and electroplating during wiring, which reduces production costs and improves the intermodulation stability of the circuit; at the same time, it is more suitable for automated production and improves production efficiency.

[0055] The present invention uses a cylindrical cavity of a multi-cavity metal profile as an outer conductor and a metal tube as an inner conductor, thereby realizing a transmission mode with the TEM mode as the main mode, reducing the radiation loss of the feed signal during the transmission process, and being almost free from interference from external signals. In addition, each cylindrical cavity is completely isolated from each other, and the coupling between each cylindrical cavity is zero, which can effectively avoid the electromagnetic waves generated by each signal transmission line from influencing each other, reducing the transmission loss of the feed signal, and greatly improving the transmission efficiency.

[0056] On this basis, the present invention can also flexibly adjust the characteristic impedance of the signal transmission line structure by changing the inner diameter of the cylindrical cavity or the outer diameter of the metal tube to adapt to different engineering design requirements. It has sufficient flexibility and applicability and has broad application prospects.

[0057] In summary, the multi-cavity coaxial transmission line structure for an antenna feeding network provided by the present invention improves the flexibility and applicability of the feeding signal transmission structure and reduces the production cost and transmission loss of the antenna feeding network.

[0058] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A multi-cavity coaxial transmission line structure for an antenna feed network, characterized in that: It includes a multi-cavity metal profile and a signal transmission line arranged in the multi-cavity metal profile; The multi-cavity metal profile is an integrally formed part, and a plurality of cylindrical cavities parallel to each other are arranged inside the multi-cavity metal profile. The plurality of cylindrical cavities penetrate the multi-cavity metal profile along the Y-axis direction and are arranged side by side in sequence along the X-axis direction; There are one or more signal transmission lines, which are respectively arranged in one or more cylindrical cavities of the multi-cavity metal profile; each signal transmission line comprises one or more sections of metal tubes, which are supported in the cylindrical cavity of the multi-cavity metal profile by a supporting connector and are coaxially arranged with the cylindrical cavity; the supporting connector is made of an insulating medium, so that the metal tube and the multi-cavity metal profile do not contact each other and are not conductive to each other; The multi-cavity metal profile is grounded, and the metal tube is electrically connected to an external power supply for transmitting a feeding signal in a TEM mode in a cylindrical cavity.

2. The multi-cavity coaxial transmission line structure for an antenna feed network according to claim 1, characterized in that: By designing the inner diameter of the cylindrical cavity or the outer diameter of the metal tube to have different size specifications, signal transmission lines with different characteristic impedances can be realized.

3. The multi-cavity coaxial transmission line structure for an antenna feed network according to claim 2, characterized in that: In the same signal transmission line, two sections of metal tubes with different outer diameters are connected by a connecting column to achieve impedance transformation of the signal transmission line; The connecting column is made of the same material as the metal tube, the outer diameter of one end of the connecting column matches the inner diameter of one section of the metal tube, the outer diameter of the middle part of the connecting column matches the outer diameter of one section of the metal tube, and the outer diameter of the other end of the connecting column matches the inner diameter of the other section of the metal tube; the two ends of the connecting column are respectively inserted and connected to the ends of the two sections of the metal tube, so that the two sections of the metal tube are connected to each other and conductive.

4. The multi-cavity coaxial transmission line structure for an antenna feed network according to claim 1, characterized in that: The multi-cavity metal profile is an aluminum profile and is made through an integrated pultrusion process.

5. The multi-cavity coaxial transmission line structure for an antenna feed network according to claim 4, characterized in that: The metal tube is a metal copper tube, an electroplated aluminum tube or an electroplated die-cast aluminum alloy tube.

6. The multi-cavity coaxial transmission line structure for an antenna feed network according to claim 5, characterized in that: The inner diameter of the cylindrical cavity is 6-9 mm, and the outer diameter of the metal tube is 1.1-5 mm.

7. The multi-cavity coaxial transmission line structure for an antenna feed network according to claim 6, characterized in that: The inner diameter of the cylindrical cavity is 8 mm, and the outer diameter of the metal tube is 1.5-4.5 mm.

8. The multi-cavity coaxial transmission line structure for an antenna feed network according to claim 1, characterized in that: The supporting connecting member is an integrally formed member, comprising two arc-shaped supporting arms located on both sides and a fixing pin located in the middle; one ends of the two arc-shaped supporting arms are connected to each other, and the middle parts are respectively bent outwards, so that an arc-shaped buckle is formed between the two arc-shaped supporting arms, and the other ends of the two arc-shaped supporting arms are arranged opposite to each other to form an opening of the arc-shaped buckle; one end of the fixing pin is connected to the connection of one ends of the two arc-shaped supporting arms, and the other end of the fixing pin extends radially to the opening of the arc-shaped buckle; The metal tube is provided with a fixing hole which penetrates radially, and the fixing pin of the supporting connection piece passes radially through the fixing hole on the metal tube. The inner diameter of the arc-shaped buckle between the two arc-shaped supporting arms matches the outer diameter of the metal tube, so that the metal tube is fixed in the arc-shaped buckle; the outer contour diameter of the two arc-shaped supporting arms matches the inner diameter of the cylindrical cavity, so as to support the metal tube in the cylindrical cavity of the multi-cavity metal profile, and make the axis of the metal tube coincide with the axis of the cylindrical cavity.

9. The multi-cavity coaxial transmission line structure for an antenna feed network according to claim 1, characterized in that: The supporting connector is in the shape of a circular ring, and its inner diameter matches the outer diameter of the metal tube, and its outer diameter matches the inner diameter of the cylindrical cavity; the supporting connector is sleeved on the outside of the metal tube to support the metal tube in the cylindrical cavity of the multi-cavity metal profile, and to make the axis of the metal tube coincide with the axis of the cylindrical cavity.

10. The multi-cavity coaxial transmission line structure for an antenna feeding network according to claim 8 or 9, characterized in that: The supporting connecting piece is made of PTFE material or PPS material.

Images